Technical Field
The present disclosure relates to an exposure system and an exposure method.
Related Art
As the progress of technology, the flat display device has been widely applied to various fields. In particular, the liquid crystal display (LCD) device has the advantages of light weight, thin, low power consumption, and no radiation, so it gradually replaces the traditional CRT display device. The LCD device can be applied to many electronic devices such as mobile phone, portable multimedia device, laptop computer, LCD TV and LCD monitor.
For example, in order to improve the multi-domain vertical alignment (MVA) technology of TFT LCD, the manufacturer utilizes a PSA (polymer sustained alignment) technology in the exposure process to enhance the optical properties of the LCD device, such as the aperture ratio and contrast. In more detailed, the PSA technology is to add light-reaction monomers into the liquid crystal molecules in the ODF (one drop filling) process. After applying electricity, the UV light is provided to cure the light-reaction monomers in the liquid crystal molecules, and the cured light-reaction monomers are arranged according to the pattern of a patterned transparent conductive layer of the TFT substrate. Accordingly, the cured light-reaction monomers can achieve the purpose of liquid crystal alignment.
In the conventional PSA exposure apparatus, the UV light is provided from a fixed light source and has a constant illuminance. Cooperating with a reflective plate, the UV light can continuously irradiate the light-reaction monomers in the liquid crystal layer of a panel located at a fixed distance, thereby inducing the light polymerization. Accordingly, the liquid crystal molecules can be aligned with multi-domain vertical alignment. However, in the exposure process of large sized panel, if the lamps of the exposure machine are too long, the lamp bending issue may incur. Otherwise, the long lamps may have uneven light intensity due to the non-uniform internal coating, which can cause the insufficient exposure evenness.